目录
- 介绍
- 1.Python+OpenCV实现
- 2.C+++OpenCV实现
- 补充
介绍
本文将介绍基于OpenCV实现视频的循环播放。
有以下三个步骤:
- 首先设置一个frame的设置参数frame_counter,值为0
- 在读帧时间,将每次加一
- 当 frame_counter 达到视频总帧数时,将当前的帧设置为 0
视频总帧数:CAP_PROP_FRAME_COUNT
设置当前的帧:CAP_PROP_POS_FRAMES
VideoCaptureProperties通用属性标识符参考地址。
1.Python+OpenCV实现
import cv2
cap = cv2.VideoCapture("001.mp4")
frame_counter = 0
while (cap.isOpened()):
ret, frame = cap.read()
frame_counter += 1
if frame_counter == int(cap.get(cv2.CAP_PROP_FRAME_COUNT)):
frame_counter = 0
cap.set(cv2.CAP_PROP_POS_FRAMES, 0)
cv2.imshow("frame", frame)
key = cv2.waitKey(1)
# ESC
if key == 27:
break
cap.release()
cv2.destroyAllWindows()
2.C++ + OpenCV实现
#include
#include
#include
int main() {
cv::Mat frame;
cv::VideoCapture cap("001.mp4");
int frame_counter = 0;
while (true)
{
cap >> frame;
if (!frame.data)
{
printf("Image not loaded");
return -1;
}
frame_counter += 1;
if (frame_counter == int(cap.get(cv::CAP_PROP_FRAME_COUNT))){
frame_counter = 0;
cap.set(cv::CAP_PROP_POS_FRAMES, 0);
}
cv::imshow("demo", frame);
char(key)=(char)cv::waitKey(1);
if(key==27)
break;
}
return 0;
}
补充
当然,OpenCV不仅能实现视频的循环播放,还能实现视频的倒放
下面将用C语言实现视频的倒放,以下是示例代码
#include
#include
#include
#include
int main(int argc, char* argv[]) {undefined
int i = 0, j = 0, k = 0;
cvNamedWindow("Example3", CV_WINDOW_AUTOSIZE);
CvCapture* capture = 0;
capture = cvCreateFileCapture("gr18.avi");
if (!capture) {undefined
return -1;
}
IplImage *out = cvQueryFrame(capture);//Init the video read
//用于确定帧数
while ((out = cvQueryFrame(capture)) != NULL) {undefined
k++;
}
cvReleaseCapture(&capture);
capture = cvCreateFileCapture("gr18.avi");
out = cvQueryFrame(capture);//没有它J会多一帧。
double fps = cvGetCaptureProperty(
capture,
CV_CAP_PROP_FPS
);
CvSize size = cvSize(
(int)cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_WIDTH),
(int)cvGetCaptureProperty(capture, CV_CAP_PROP_FRAME_HEIGHT)
);
CvVideoWriter *writer = cvCreateVideoWriter(
"gr13.avi",
CV_FOURCC('M', 'J', 'P', 'G'),
fps,
size
, 1
);
IplImage* logpolar_frame = cvCreateImage(
size,
IPL_DEPTH_8U,
3
);
//out = cvCloneImage(img);
int booll = 1;
while ((out = cvQueryFrame(capture)) != NULL)
{undefined
i = 0;
j++;;
booll = 0;
if (j == k)//用于从第J帧开始写入
{undefined
cvShowImage("Example3", out);
cvWaitKey(1);
cvWriteFrame(writer, out);
k--; j = 0;
//重复初始化
capture = cvCreateFileCapture("gr18.avi");
out = cvQueryFrame(capture);
}
//j++;
if (k == 0)break;
}
printf("||%d %d", k, j); getchar();
cvReleaseVideoWriter(&writer);
cvReleaseImage(&logpolar_frame);
cvReleaseCapture(&capture);
//cvReleaseCapture(&capture);
cvDestroyWindow("Example3");
return(0);
}